On Fedora rawhide we get the following build failure:
In file included from shared/systemd/src/basic/alloc-util.c:3:
./shared/systemd/sd-adapt-shared/nm-sd-adapt-shared.h:114:21: error: static declaration of 'gettid' follows non-static declaration
114 | static inline pid_t gettid(void) {
| ^~~~~~
In file included from /usr/include/unistd.h:1170,
from /usr/include/glib-2.0/gio/gcredentials.h:32,
from /usr/include/glib-2.0/gio/gio.h:46,
from ./shared/nm-utils/nm-macros-internal.h:31,
from ./shared/nm-default.h:293,
from ./shared/systemd/sd-adapt-shared/nm-sd-adapt-shared.h:22,
from shared/systemd/src/basic/alloc-util.c:3:
/usr/include/bits/unistd_ext.h:34:16: note: previous declaration of 'gettid' was here
34 | extern __pid_t gettid (void) __THROW;
| ^~~~~~
glibc supports now gettid() call ([1]) which conflicts with our compat
implementation. Rename it.
[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=1d0fc213824eaa2a8f8c4385daaa698ee8fb7c92
(cherry picked from commit 10276322bd)
NetworkManager is single-threaded and uses a mainloop.
However, sometimes we may need multiple threads. For example, we will
need to write sysctl values asynchronously, using the glib thread-pool.
For that to work, we also need to switch the network-namespace of the
thread-pool thread. We want to use NMPNetns for that. Hence it's better
to have NMPNetns thread-safe, instead of coming up with a duplicate
implementation. But NMPNetns may want to log, so we also need nm-logging
thread-safe.
In general, code under "shared/nm-utils" and nm-logging should be usable
from multiple threads. It's simpler to make this code thread-safe than
re-implementing it. Also, it's a bad limitation to be unable to log
from other threads. If there is an error, the best we can often do is to
log about it.
Make nm-logging thread-safe. Actually, we only need to be able to log
from multiple threads. We don't need to setup or configure logging from
multiple threads. This restriction allows us to access logging from the
main-thread without any thread-synchronization (because all changes in
the logging setup are also done from the main-thread).
So, while logging from other threads requires a mutex, logging from the
main-thread is lock-free.
For better or worse, we already pull in large parts of systemd sources.
I need a base64 decode implementation (because glib's g_base64_decode()
cannot reject invalid encodings). Instead of coming up with my own or
copy-paste if from somewhere, reuse systemd's unbase64mem().
But for that, make systemd's basic bits an independent static library
first because I will need it in libnm-core.
This doesn't really change anything except making "libnm-systemd-core.la"
an indpendent static library that could be used from "libnm-core". We
shall still be mindful about which internal code of systemd we use, and only
access functionality that is exposed via "systemd/nm-sd-utils-shared.h".
